The humbucker, or humbucking pick-up, is a feature of most of the electric guitars made by Epiphone and its parent company, Gibson.
The humbucker is a two-coil pick-up with coils of reversed polarity, reverse wound, and connected in series. The name is derived from the fact the design of the pick-up significantly reduces the noise and interference associated with single coil pick-ups used in other guitars, such as Fender’s Stratocaster. In other words, they ‘buck the hum.’
Guitars which are fitted with humbuckers have one at the neck and one at the bridge, along with a three-way switch to choose either pick-up individually, or both together. Humbuckers are often covered with a metal plate; where they are uncovered, the coils and six magnetic pole pieces are clearly visible.
Originally invented by a Gibson employee, Seth Lover, in 1957, the humbucker is strongly associated with Gibson, and in particular the Les Paul, although it’s widely used by other manufacturers. Like every other guitar pick-up, the humbucker works by ‘picking up’ the vibrations of the guitar strings, which then induce an alternating current in its coils. The key difference between it and single coil pick-ups is that it is unaffected by the electromagnetic interference which causes an audible hum from a single coil pick-up.
The reason for this is that the twin coils are reverse wound and reversed in polarity, this means that the electromagnetic interference induces current in opposing directions in each coil and the interference from each coil cancels out that in the other. By contrast, the signal from the vibration of the strings is increased. This is known as common-mode rejection.
The humbucker is known for its fat, warm tone which differs from the clear, bright tone produced by single coil pick-ups.This tone is key to the sound of guitars like the Les Paul and SG, as well as archtop guitars like the Casino and Sheraton. The reason for the tone is that the two coils resonate at different frequencies and therefore, the resonant peak is broader than that of a single coil pick-up.